[97Formula]

I have a strange issue that is still lingering even after a complete fuel system overhaul (new fuel pump, power-cleaned injectors and throttle body).

On a cold start, it will fire up and rise to 1100RPM, but drops to 800RPM and stay there for 1/2 second, and finally rise back to 1200RPM and stay there until warm, then go back to 800RPM (normal warm idle). The idle speed pretty much stays put and never stalls or surges except that little bit on a cold start, but I do notice a little roughness at a warm idle at 800RPM (tach needle doesn't move but I do feel occasional "jolts" as the engine idles). When I drive normally (or drive at WOT), car runs awesome. No stumble or hesitation as I press the gas pedal. No SES light either.

Any ideas? Already tried another MAF sensor with no change. Does the throttle body power clean service include the IAC valve too? The car used to just go straight to 1200RPM on a cold start (problem did exist before having all this work done). Thanks!